Help Converting Penis Mod to Opposite Frame - Mesh Breaks In-game

[Kino-kun]

I'm not sure if this is the right sub-forum to be posting this so I apologize in advance if it should have been posted elsewhere.

 

I'm currently attempting to convert some of the male-exclusive Simdulgence penises to work on feminine frames. Everything looks fine in blender and s4s, however once I load it in-game the mesh breaks and warps. I attempted two different ways to "frankenmesh" the penis from the masculine frame to the feminine one. Both result in the testicles warping and stretching away from the body, which I found weird since one method kept the testicles from another of Simdulgence's penises designed for feminine frames.

 

From what I've gathered I believe it's a problem with needing to transfer weights. I've found a couple tutorials for transferring weights between meshes but when I attempt to follow them it seem to make the mesh break more. I'm sure I'm missing a step but it's difficult to find help with my specific instance of this issue considering it's adult content. If anyone familiar with mesh editing could give some advice it'd be much appreciated. Thanks.